1. Field of the Invention
The present invention relates to a flexible pipe joint apparatus for use in a fluid (e.g., water) transport pipe system for maximally absorbing an external force such as a compression or tensile force applied to a pipe of the fluid transport system due to an earthquake, differential settlement, thermal expansion or contraction of the pipe per se, thus preventing resultant damage at a weak portion of the pipe. The invention more particularly relates to a flexible pipe joint apparatus of the above-noted type which includes a receiving tubular member, an inserting tubular member insertable into and connectable with the receiving tubular member along a tube axial direction, a stopper portion formed on an outer peripheral face of the inserting tubular member, the stopper portion projecting radially outward from the outer peripheral face, and a retaining portion formed in an inner peripheral face of the receiving tubular member, the retaining portion coming into contact with the stopper portion of the inserting tubular member so as to prevent relative slidable displacement between the two tubular members at least on a withdrawal side beyond a predetermined relative axially slidable range of the tubular members.
2. Description of the Related Art
A conventional flexible fluid-transport pipe joint apparatus is shown in FIG. 13. As shown, this apparatus includes a receiving tubular member 1 having a connecting flange 1A for connection to a fluid transport device such as a sluice valve, a fluid transport pipe, etc. and an inserting tubular member 5 insertable into the receiving tubular member 1 and having a connecting flange 5A for connection to the fluid transport pipe such as a transport pipe. In the inner peripheral face of the receiving tubular member 1, there are formed a first annular groove 7 for restricting a relatively slidable range between the two tubular members 1, 5 and also a second annular groove 9 for fitting therein an elastic seal 8 in order to seal the gap formed between the inner peripheral face of the receiving tubular member 1 and the outer peripheral face of the inserting tubular member 5. Adjacent the axial end of the outer peripheral face of the inserting tubular member 5, there are formed a third annular groove 51 for fitting therein a substantially C-shaped retaining ring 50 elastically deformable for radial expansion to act as a xe2x80x98stopper portionxe2x80x99 and a tapered guide face 52 for guiding the retaining ring 50 into the third annular groove 51 while allowing radial elastic expansion of this ring 50. The first annular groove 7 is formed by and between a wall portion 1B on the base-end side and a further wall portion 1C on the opening side of the inner peripheral face of the receiving tubular member 1. These wall portions 1B and 1C together constitute a xe2x80x98retaining portionxe2x80x99 for coming into abutment against the retaining ring 50 fitted in the third annular groove 51 of the inserting tubular member 5 and also with a leading end face of this inserting tubular member 5 along the tube axial direction X, thereby to limit relative slidable displacement between the two tubular members 1, 5 on the withdrawal (pulling) side and on the inserting (pushing) side, respectively, within a certain tolerance.
With such conventional fluid-transport flexible pipe joint apparatus, when the receiving tubular member 1 and the inserting tubular member 5 are to be connected with each other, the inserting tubular member 5 cannot be inserted into and connected with the receiving tubular member 1, with the retaining ring 50 being kept fitted within the third annular groove 51 of the inserting tubular member 5. Then, as illustrated in FIGS. 14 and 15, prior to the connecting operation of the tubular members 1, 5, it is necessary first to attach a first fitting jig 53 and a second fitting jig 54 within the receiving tubular member 1. The first fitting jig 53 is capable of receiving the retaining ring 50 inserted into the receiving tubular member and can be disassembled into a plurality of sections in the peripheral direction. Like the first fitting jig 53, the second fitting jig 54 also can be disassembled into a plurality of sections in the peripheral direction. And, this second fitting jig 54 includes an annular receiving face 54a for retaining the retaining ring 50 from the radially inside thereof coaxially with the receiving tubular member 1 and a tapered cam face 54b for radially expanding and shifting the retaining ring 50 received by the first fitting jig 53 to the tapered guide face 52 of the inserting tubular member 5 as the face 54b comes into contact with the leading end of the inserting tubular member 1 and is subsequently moved therewith during the insertion of the tubular member 1. After completion of the connecting operation of the two tubular members 1, 5, it is necessary to disassemble and remove the first and second fitting jigs 53, 54 set inside the receiving tubular member 1 one after another. In this manner, the connecting operation of the two tubular members 1, 5 is very troublesome.
Moreover, the entire fluid transport flexible pipe joint apparatus requires the retaining ring 50 in addition to the two tubular members 1, 5; and the fitting grooves therefor need to be formed with high machining precision in the inserting tubular member 5. Hence, high manufacture costs tend to ensue due to the great number of the parts and the great number of the manufacturing steps as well.
The present invention has addressed the above-described state. A primary object of the invention is to provide a flexible pipe joint apparatus for fluid transport, which apparatus allows the connecting operation of the receiving tubular member and the inserting tubular member to be effected efficiently and easily without using any special jigs and which also achieves reduction in the manufacturing costs of the apparatus.
For accomplishing the above-noted object, according to the present invention, a flexible fluid-transport pipe joint apparatus includes a receiving tubular member, an inserting tubular member insertable into and connectable with the receiving tubular member along a tube axial direction, the apparatus comprising:
a stopper portion formed in an outer peripheral face of the inserting tubular member, the stopper portion projecting radially outward from the outer peripheral face; and
a retaining portion formed in an inner peripheral face of the receiving tubular member, the retaining portion coming into contact with the stopper portion of the inserting tubular member so as to prevent slidable displacement between the two tubular members at least on a withdrawal side in a predetermined relative slidable range of the tubular members;
wherein the stopper portion includes a plurality of projections formed at a plurality of positions along a periphery of the inserting tubular member; and
the retaining portion of the receiving tubular member includes a plurality of detaching recesses, each said recess allowing passage of each of the projections axially relative to the detaching recess only when the receiving tubular member and the inserting tubular member are located in a predetermined phase relationship with each other.
Here, the term xe2x80x9cphasexe2x80x9d means a relative rotational relationship between the two tubular members about the tube axis.
According to the above-described construction proposed by the invention, for connecting the receiving tubular member and the inserting tubular member with each other, the two tubular members are first adjusted in the peripheral direction into a predetermined phase relationship (i.e. a predetermined connecting position) with each other so as to bring the projections and the detaching recesses into agreement. Under this condition, the tubular members are then moved axially closer or deeper to each other for allowing each recess to pass each projection. Thereafter, the two tubular members are peripherally rotated relative to each other from the predetermined connecting position to a predetermined retained position.
With the realization of the retained position above, when a mutually withdrawing, i.e. separating force is applied to the tubular members, withdrawal of one tubular member from the other tubular member may be effectively resisted as all or some of the projections of the inserting tubular member come into abutment against the retaining portion of the receiving tubular member along the axial direction of the tubular members.
As described above, with the construction of the present invention, the connecting operation of the receiving tubular member and the inserting tubular member requires only two steps, i.e., the step of axially engaging the tubular members relative to each other under the predetermined phase condition and the second step of rotating these tubular members relative to each other under this condition. Hence, this construction eliminates the troublesome operation of assembling and disassembling the jigs within the limited space inside the receiving tubular member, so that the connecting operation of the two tubular members can be effected easily and efficiently.
Moreover, the precision required for forming the projections on the inserting tubular member and the detaching recesses in the receiving tubular member may be only such as to allow mutual passage therebetween under the predetermined phase relationship. Hence, any special high-precision machining of these projections and recesses is not needed. Also, the number of parts can be reduced, compared with the conventional construction described above.
According to one preferred embodiment of the present invention, the flexible pipe joint apparatus further comprises a temporarily fixing means for temporally fixing the receiver and inserting tubular members to be non-rotatable relative to each other when the tubular members are under a retained condition which is realized by rotating the inter-connected receiving and inserting tubular members relative to each other from said predetermined phase relationship.
With the above-described construction, when during e.g., shipment of the apparatus to a site of installment and various external forces are applied inadvertently to the receiving tubular member and the inserting tubular member connected with each other, the retaining portion (i.e., detaching recesses) of the receiving tubular member and the stopper portion (i.e., the projections) of the inserting tubular member may be maintained with a predetermined peripheral depth of engagement with each other sufficient to resist the effect of the external forces. Further, when the receiving tubular member and the inserting tubular member are to be flange-connected with various fluid transport devices such as a sluice valve, fluid transport pipe by releasing the temporary fixing means, it becomes necessary to slightly rotate the receiving tubular member and the inserting tubular member for their mutual phase alignment. In such case, the above-described construction can effectively prevent occurrence of accidental peripheral or rotational agreement between the projections of the inserting tubular member and the detaching recesses of the receiving tubular member.
Therefore, the above construction assures reliable and firm non-withdrawable connection between the two tubular members while facilitating handling of the apparatus during its shipment to a user or to a site of installment.
Preferably, the flexible fluid-transport pipe joint apparatus further comprises a covering means extending over a connecting portion between the outer peripheral face of the receiving tubular member and the outer peripheral face of the inserting tubular member so as to cover the detaching recesses from the above.
With the above construction, while the apparatus retains the effect of allowing efficient and facilitated connecting operation between the two tubular members due to the formation of the detaching recesses which allow axial passage of the respective projections of the inserting tubular member only when the two tubular members are under the predetermined phase relationship, the covering means covers or protects the detaching recesses, so that an elastic seal or the like to be interposed between the inner peripheral face of the receiving tubular member and the outer peripheral face of the inserting tubular portion may be effectively prevented from being exposed to the ambient air or the like. Consequently, weatherability of such interposing element as the elastic seal may be improved advantageously.
Still preferably, the plurality of projections and the plurality of detaching recesses are arranged in symmetry with respect to a diametrical center line extending through the common axis of the tubular members and the plurality of detaching recesses are peripherally distributed such that the peripherally adjacent pairs of the detaching recesses form center angles relative to the tube axis which angles are different from one another.
With the above construction, when the receiving tubular member and the inserting tubular member are to be connected with each other, the predetermined phase relationship characterized by the positional agreement between the projections of the inserting tubular member together forming the stopper portion and the detaching recesses of the receiving tubular member together forming the retaining portion is realized only one time during the total rotation (360 degrees).
Therefore, the two tubular members can be rotated relative to each other by the maximum angle of rotation of 180 degrees from the predetermined phase condition (i.e., the connecting position) where the projections of the inserting tubular member and the detaching recesses of the receiving tubular member are in peripheral alignment with each other to the predetermined retained position. Hence, when the receiving tubular member or the inserting tubular member is to be flange-connected with a fluid transport device such as a sluice valve, fluid transport pipe or the like by releasing the temporary fixing means and the receiving tubular member and the inserting tubular member are to be slightly rotated relative to each other for mutual alignment, it is possible to ensure sufficient engagement peripheral depth between the retaining portion of the receiving tubular member and the projections of the inserting tubular member. Consequently, the two tubular members may be connected reliably and firmly while effectively preventing inadvertent withdrawal of one from the other.
Yet, as the projections and the detaching recesses are formed in symmetry with each other relative to the diametrical center line extending through the common axis of the tubular members, it is easy for a user to visually find the predetermined phase relationship. So that, the phase adjustment between the inserting tubular member and the receiving tubular member may be effected easily.
Still preferably, the inserting tubular member includes, on an inner peripheral face and at portions corresponding to the projections formed on the outer peripheral face thereof, a plurality of projections which project radially inward.
With the above construction, while the apparatus retains the effect of allowing efficient and facilitated connecting operation between the two tubular members due to the formation of the detaching recesses which allow axial passage of the respective projections of the inserting tubular member only when the two tubular members are under the predetermined phase relationship, the inner peripheral face portions of the inserting tubular member may be reinforced because of the presence of inward projections, so that inadvertent withdrawal displacement between the two tubular members can be resisted more effectively and reliably.
Still preferably, the temporary fixing means is detachably attached to a connecting flange of the inserting tubular member and also to a plurality of projecting connecting portions formed at a plurality of peripheral positions in the outer peripheral face of the receiving tubular member adjacent a receiver opening thereof, and an attaching portion for the covering means is formed in the outer peripheral face of the receiving tubular member and between an end face of the receiving tubular member adjacent the receiver opening thereof and said connecting portions.
With the above construction, by forming the connecting portions on the receiver-opening side portion of the outer peripheral face of the receiving tubular member adjacent the connecting flange of the inserting tubular member, the temporary fixing means may be formed compact with respect to the axial direction of the tubular members. In addition, by utilizing the axial gab between the receiver-opening side end face and the connecting portions as the attaching portion for the covering means, this covering means may be attached readily and speedily.
Further and other features and advantages of the present invention will become apparent from the following detailed disclosure of the preferred embodiments thereof with reference to the accompanying drawings.